Dry cell composition



E. M. OTTO DRY CELL COMPOSITION Oct. 2, 1951 2 Sheets-Sheet 1 Filed June 27, 1946 khwfkwi QN f m e g hl m E. M. OTTO DRY CELL COMPOSITION Oct. 2, 1951 Filed June 27, 1946 N .SIG O Q o O 3 wa/vvbo/v EARL M. orTo www Patented Oct. 2, 1951 UNITED STATES OPfPICE` @566,491 DRY CELL COMPOSITION Earl Otto, ;Washin=g.jton, D.' 6;'.

Application .Iune127;.:1 946, Serial No;679,637 v 4 Claims.- (Gl. 13d-.1534.)

(Granted under theaet of March 3, 1883, Vas amended April 30, 1928; 370 0. G. 757) characteristics over all or part Aofthe range of temperature/from 20 C.k to 50 C.

Calcium chloride fhas previously been proposedr asa complete substitute for ammoniumchloride for low temperature dry cells. For other reasons, it has also been added in small quantities to zinc chloride-ammonium chloride mixtures, but itl isthewpurposeof this`A invention. to show that only'in certain limited proportions can aquemonium and zincbe made-to serve as satisfactory' electrolytes at` abnormally lowtemperatures. No one has shown heretofore that appreciable quantities of calcium chloride, ammonium chlorideV and zinc chloride in aqueous solutions are com-V patible at 20 to 45 CL I have found that,

when the concentration ofthe dihydrate of cal-,

cium chloride is between %V and 30% and that ofthe zinc chloride i'sbetween 10%- and 40 the solubility ofl ammoniumchloride may bei even' greater than at 30 C. I have found that' some electrolytes from this region give dry cells with goed performance at low temperatures. Byj using aslittle zinc chloride as required tol preventor'lreduce-freezing of' theelectrolyte at a--certain low temperature, goed cel-lperformance Aatthat temperature is obtained. It is not necessary that, forbest electrical performance, all the ammonium-A chloride be in solution at the specified 10W temperature. Thus, the electrolyte of one of the preferred formulas begins crystallization at. 21"v C. This procedure is in accordwithethe common practice of incorporatinginthe ordinary dry cell much more ammonium chloride than will dissolve atfroomtemperature.

Many/oi the attendant advantages of thisfin'- ventionwill be. readily appreciated as the same becomes. better understood by. reference tothe following detailed description when considered .connection withn the.. accompanying drawings Wl'iereinz'v Figure 1 isatriaxial vdiagramindicating freezing points of electrolytes having as their ingredients 'calciumchloride, zinc chloride;- ammonium chlorider and Water-"1.v The temperaturesV recorded 2; are those at Which. thef-rst-signsof crystallization appear.. Themarking 0 `is usedto .denotex that the initial freezing point is above: 0 C;, but; below plus 25 C.

Figure: 2 is :a triaxial diagram of results of capacity tests performed on dry cells having the electrolytes of Figure 1'.

The results of initial 4-ohmand lf-olfirrreon-f` tinus-us tests on several lotsof cells approximates-1 ly 21A; inches high by/'lllinchesdiameterf-re ferred to in the art as D-size cells, are given in the falloir/ingv table,Y Forcomparison purposes results on. an ordinary ammonium chloride type cell are included. The first threelots Were composed of? naturalmanganese .dioxide ore. and. graphite. in: a ratio of 21/2 to 1 Wet down withL electrolyte Whereas the next' 3 were composed of naturalore andi acetyleney black' in aratio of 8y to 1. The compositions ofthe electrolyte used for mixand paste are: givenl ini the table. For the paste Wall, flourand starchintheratio of l to 2 were added to a quantity of electrolyte until the paste, when: complete-ly gelatinized,l hadthe desired consistency. Mercurio chloride Wasadded to the pasteL in such a quantity thaty each D. size zinc can had approximately 0.22 g. It is seen from the table inlaat-10g. of ammonium-chloride added tol a-mixture -of 13g.- of-dihydrate ofcal-cium chloride, 21 g. of zinc chloride and- 66ml'. of Water gives better output zat- 30 C. than 5 g. or 15 g. of `ammonium chloride added to the same mixture.- For` other temperatures, the optimum-ly quantityof ammonium chloride may bev -more orfless than this 10 g., as high as. 20 `gebeingusI-f able., More data on initial 4-ohm capacity tests at4 30m CLjarey givenv inligure` 2 of the drawings, which is also a triaXial diagraml of the three electrolyte components: CaClaEI-IZO, 'ZnCla H2O'. It' isf clearly seen that for this` particular test at this` particular temperature best results arek Obtained with a composition of :26.5%

CaClaZI-IO* and 15% ZnClz, by weight, to which is added ammonium chloride equal to 10% of the` total weight of thisicomp'osition. Increasing any oneA component and decreasing another in a; regularmanner causesr a taperingA oiif'of the capacity, the effect beingmuch-1 greater in' some directions than others. The compositionof the carbon-manganese materials forms no` part lof this'A invention; it Vbeing understoodthat any-or, all are usable with the electrolyte claimed inthi's invention. Likewisethe nature of the separator Wall may` be-'ofA the cereal, thermo-plastic O11l any other typeg-thef` cnlyf condition being that the component ofi tlrel-Wall* as Wellf as of the black mix, be compatible with the electrolyte claimed in this invention.

Results of electrical tests Continuous Tests at 30 O.

Electrolyte +21 C., 3o c., 4-onm 11i-ohm ocv1 oevi oac1,.211,o znoi, 11,0 N11.c1 gtilz 0 '711`0v (Illltil, o #ov a. a. ml. y. v. v. t. Mn. v. Mn. 13 21 es 5 1. 57 1. 52 1. 12 14 1. 39 260 13 21 es 10 1. 5s 1. 53 1. 20 30 1. 41 41s 13 21 6e 15 1. 59 1. 56 1. 17 2e 1. 37 282 a0 50 10 1. e3 1. 60 1. 3s 107 1. 53 800 25. 5 15 58. 5 10 1. ee 1. e2 1. 41 119 1. 55 73s 2s. 5 2o 53. 5 10 1. 66 1. 62 1. 25 s2 1. 54 ssa ordinary NH4C1 type 1. 5s 1. 2s o. o1 0 0. 05 o 1 OCV denotes open circuit voltage. I CCV denotes closed circuit voltage.

There are many formulas possible Within the ponents f approximately in the proportionsv Vby( scope of this invention, the following being ex- Weight indicated: Y 'Y amples Ony- 26.5, 051012.21120 El t El t 15.0, ZnC12 @C lO- 8C TO- e e 10.0, NHlci 115812.21110 -g-. go 26.3 3. A dry ceu characterized by a relatively high u 1g 11519 30 capacity at low temperatures comprising the fol- 50 58-5 lowing respectively, approximately in the Weight proportions stated: Reference to the above table shows that these Bobbi-n @polari-er Composition. two electrolytes are operative at 10W tempera- Mnoz g 200 tures and deliver a relatively constant output for Acetylene black g 2 5 a considerable perlod of time against closed cir- Electrolyte m1 .75 cuit resistance.

The compositions of the electrolytes have been Paste compo-917510 designed for initial performance of dry cells. F1001' g 5-7 Since certain materials are partially consumed 40 Starch' g 11-4 on shelf, it is understood that such quantities, EleCi'fIOlYe "H11- 85. as needed for satisfactory shelf life, may be HgC12 e;---. --g 0202 added- Y Electrol te com osztzon A preferred complete formula for the bobbin v y p Grams and paste compositions comprises: 6 031312.21120 265 Bobbin depolarizer composition ZI1C12 15.0 Mnoz g-- 200 c Acetylene Black g 25 y Electrolyte #2 ml. approx" 75 o 4. VAn electrolyte composition for a dry cell conu Paste composition sting essentla y 1n the proport1ons by weight Flour g-- 5.7 Gms Starch g 11-4 Calcium dicmcride dihydrate 21.2 Eleotrolyte #2* ml-- 86. Zinc Chloride 212 Mercurio chloride g 0.202 vvatll'` 5,7 6 While particular or specic compositions have Ammonium Ychloride 10.0 been given in this table, it is not desired to be Y v strictly limited thereto, as some Variation from 110,0 the particular percentages given may be made without affecting the performance of the cells. EARL'M OTTO' Such variations are included Within the scope of REFEREN ES ITED this invention to the extent as defined by the C C herewith appended Claims The followmg references are of record 1n the The invention described herein may be manume )9h15 'patentfactured and used by or for the Government of 05 UNITED STATES PATENTS the United States of America for governmental Number Name l :Datev purposes Without the payment of any royalty 11939949 Jaeger 0G91, 1912 thereof? o? therefor' 1,123,843 Burger Jan. 5, 1915 I 01mm 1,430,727 De olaneta oct. 3, 1922 1. An electrolyte compos1t1on for 10W tempera- 70 1,497,317 Askin June 10, 1924 ture dry cells comprising a solution of from 40 2,403,571 Wke July 9, 1945 to H2O, 10 to- 30% CaCl2.2H2O and 10 to Y 40% znclz, and a quantity of NH4C1 equal to OTHER REFERENCES 5 to 20% by Weight of said solution. Kameyama et al., J. Society of Chemical Irl- 2. An electrolyte composition for dry cells dustry,lJapan, volume 39, page 375l (1936i. 

1. AN ELECTROLYTE COMPOSITION FOR LOW TEMPERATURE DRY CELLS COMPRISING A SOLUTION OF FROM 40 TO 65% H2O, 10 TO 30% CACL2.2H2O AND 10 TO 40% ZNCL2, AND A QUANTITY OF NH4CL EQUAL TO 5 TO 20% BY WEIGHT OF SAID SOLUTION. 